284: Bosch ME7.01 Engine management system, B5254T2

284: Bosch ME7.01 Engine management system, B5254T2

S60 (-09), 2005, B5254T2, AW55-50/51SN, L.H.D

7/11/2014 PRINT

284: Bosch ME7.01 Engine management system, B5254T2

Accelerator pedal (AP) position sensor

Air conditioning (A/C) pressure sensor

Air conditioning (A/C) relay

Brake light switch

Camshaft reset valve (Continuous variable valve timing (CVVT))

Camshaft sensor

Clutch pedal sensor (manual transmissions only)

Cooling fan for control modules, turbocharger (TC) (certain markets only)

Electronic throttle unit

Emissions warning lamp

Engine coolant level sensor

Engine coolant temperature (ECT) sensor

Engine cooling fan (FC) / engine cooling fan (FC) control module

Engine speed (RPM) sensor

evaporative emission system (EVAP) valve

Fuel pressure sensor / fuel temperature sensor (only vehicles with demand controlled fuel pumps)

Fuel pump (FP) relay, (2002–2004)

Fuel pump (only vehicles with demand controlled fuel pumps)

Fuel pump control module (only vehicles with demand controlled fuel pumps)

Heated oxygen sensors (HO2S)

Ignition coils

Ignition switch

Immobilizer

Injectors

Knock sensor (KS)

Page 1 of 42284: Bosch ME7.01 Engine management system, B5254T2

11/7/2014http://localhost/Vida/jsp/information/xml/xmlDocPrintPreview.jsp

Leak diagnostic unit (certain markets only)

Main relay (system relay)

Manifold absolute pressure (MAP) sensor, intake (turbocharged engines only, 2002-2004)

Manifold absolute pressure (MAP) sensor, intake (turbocharged engines only, 2005-)

Mass air flow (MAF) sensor (2002-2004)

Mass air flow (MAF) sensor (2005-)

Oil level sensor (2004-, certain markets and models only)

Outside temperature sensor

Temperature sensor, intake (turbocharged engines only, 2002-2004)

Throttle position (TP) sensor

Turbocharger (TC) control valve

Design

Ignition switch

The Engine Control Module

(ECM) uses the signal from

the ignition switch to detect

when the ignition key has

been turned to position II or

III. When the key is in the

ignition position (position II)

or starting position (position

III) a high signal (Ubat) is

transmitted from the ignition

switch to the engine control

module (ECM). The engine

management system prepares

for start-up (for example,

temporarily activates the fuel

pump (FP) relay). When the

flywheel in the engine rotates,



the engine speed (RPM)

sensor signal is used to keep

the fuel pump (FP) relay

activated.

The fuse in the fusebox in the

passenger compartment

supplies current to the ignition

switch.

The central electronic module

(CEM) can diagnose the

ignition switch.

Immobilizer

See Design and Function,

Immobilizer.

Fuel pump control module

(only vehicles with demand

controlled fuel pumps)

The fuel pump control module

powers the fuel pump and

regulates the output of the

pump. The fuel pressure

changes with the output of the

pump.


is supplied with battery

voltage by the fuel pump (FP)

relay and is grounded in the

car body. The fuel pump (FP)

relay is controlled by the

central electronic module

(CEM) when requested by the

engine control module (ECM).

The engine cannot be started

if the power supply to the fuel

pump control module is faulty

because the fuel pump will not

then be powered.


is controlled by the engine

control module (ECM) via

serial communication. The fuel

pump control module then

controls the fuel pump by

transmitting a PWM voltage on

the ground lead for the fuel

pump. This means that the

voltage drop across the pump

changes, and with it the



output of the fuel pump. Also

see Function:Fuel pressure

regulation (only vehicles with

demand controlled fuel

pumps) .

There are no diagnostics for

the fuel pump control module.

The engine control module

(ECM) has diagnostics for fuel

pressure regulation and the

associated components. Also

see Fuel pressure regulation,

diagnostics .

The pulse-width modulated

(PWM) signal from the engine

control module (ECM) to the

fuel pump control module can

be read using VIDA.


is on the outside on the right-

hand side of the fuel tank.

Fuel pump (only vehicles

with demand controlled

fuel pumps)

The function of the fuel pump

is to ensure that the pressure

is correct at the delivery lines

for the injectors when

requested by the fuel pump

control module.

The fuel pump consists of:

1. An electrical pump with

an integrated safety

valve

2. A pressure equalization

valve. This valve

equalizes rapid pressure

peaks which occur, for

example, when the

injectors close during

engine braking. It also

contains a non-return

valve which ensures that

the pressure in the

system does not drop

when the engine is

switched off

3. Fuel level sensor



4. Fuel filter, cannot be

replaced separately

5. Relief valve, releases

fuel into the pump

housing

6. Ejector pump,

continuously fills the

pump housing with fuel.

The fuel always flows

from the fuel pump

through the ejector and

back to the pump

housing.

The fuel pump is supplied with

battery voltage by the fuel

pump control module and is

grounded in the car body.


(ECM) has diagnostics for the

fuel pump function to ensure

that the pressure is correct.

Also see Fuel pressure

regulation, diagnostics .

The fuel pump can be

activated and its status read

off using VIDA.

The pressure in the fuel rail

can be measured by

connecting a manometer to a

nipple. This nipple is on the

right-hand end of the fuel rail.

Brake light switch

The task of the brake light

switch is to provide the engine

control module (ECM) with

information about the position

of the brake pedal.

A signal is transmitted to the

engine control module (ECM)

when the brake pedal is



pressed. The engine control

module (ECM) disengages the

cruise control (if activated).

The brake pedal sensor also

disengages cruise control. For

further information, see

Design and Function, Brake

system, design.

The brake light switch is

supplied with power from the

ignition switch (terminal 30).

When the brake pedal is

depressed the switch closes

and a high signal (12 V) is

transmitted to the engine

control module (ECM).


(ECM) can diagnose the brake

light switch. The status of the

switch can be read using

VIDA.

The brake light switch is on

the pedal box by the brake

pedal.

Clutch pedal sensor

(manual transmissions

only)

The clutch pedal sensor

provides the Engine Control

Module (ECM) with information

about the position of the

clutch pedal.

This information is used by the

control module to switch off

the cruise control.

The sensor signal is also used

by the control module to

prevent engine start if the

clutch pedal is not pressed

(certain markets).

The sensor consists of a

sliding potentiometer which is

supplied with power by the

control module (signal) and

which is grounded in the

control module.

The resistance in the sensor

drops when the clutch pedal is



pressed.


(ECM) can diagnose the clutch

pedal sensor. The status

(position) of the sensor can be

read using VIDA.

The sensor is on the pedal box

by the clutch pedal.

Air conditioning (A/C)

pressure sensor

The air conditioning (A/C)

pressure sensor detects the

pressure in the high-pressure

side of the air conditioning

(A/C) system. This is so the


can control:

� engine cooling fan (FC)

start

� stopping the compressor

if the pressure in the air

conditioning (A/C) is too

high

� constant idle speed

compensation for the air

conditioning (A/C)

compressor load.

The sensor is linear. It is

grounded in the control

module and supplied with a 5

Volt current from the control

module. A linear signal

(between 0-5 V depending on

the pressure in the air

conditioning (A/C)) is

transmitted to the control

module. At 0.25 kPa or lower,

the voltage is 0 V, at 3100 kPa

the voltage is approximately

4.75 V. Low pressure results

in low voltage, high pressure

in high voltage.


(ECM) can diagnose the air

conditioning (A/C) pressure

sensor. The sensor value can

be read off using VIDA.




pressure sensor is positioned

on the high pressure delivery

line for the air conditioning

(A/C) system.

Heated oxygen sensors

(HO2S)

� 5 cylinder engines have

two heated oxygen

sensors (HO2S), front

and rear

� 6 cylinder engines have

four heated oxygen

sensors (HO2S), front

and rear for bank 1

(cylinders 1-3) and front

and rear for bank 2

(cylinders 4-6)

� XC90s with 6 cylinder

engines utilize the Y-

concept, where the

engine has two heated

oxygen sensors (HO2S)

bank 1 (cyl. 1 –3), bank

2 (cyl. 4 –6) and a rear

heated oxygen sensor

(HO2S) (bank 1).

Front heated oxygen sensor (HO2S)

The front heated oxygen sensor (HO2S)

is used to provide the Engine Control

Module (ECM) with information about the

remaining oxygen content of the exhaust

gases in front of the three-way catalytic

converter (TWC). This is so that the

Engine Control Module (ECM) can

continually check the combustion so that

λ=1. λ=1 is the ideal fuel-air ratio, with

14.7 kg air/1 kg fuel.

The heated oxygen sensor uses current

regulation and its signal characteristic is

linear. With a linear signal characteristic,

the amplitude of the signal curve is low

when changing the oxygen content in the

exhaust gases. The probe consists of a

preheating element (see "Pre-heating

heated oxygen sensors (HO2S)") and the

actual lambda sensor. The lambda

sensor is an oxygen sensitive ceramic

body consisting of zirconium oxide. The

control module supplies power to the

ceramic body, which reacts to the

oxygen content of the exhaust gases.

This in turn affects the signal to the

engine control module (ECM). In order to

determine the oxygen content in the

exhaust pipe, the heated oxygen sensor

needs reference air from the surrounding

air. This reference air reaches the heated



oxygen sensor via the wiring.

Caution! The wiring for the heated

oxygen sensors (HO2S) must not be

trapped or damaged in any way. The

connectors for the heated oxygen

sensors (HO2S) must not be greased

under any circumstances. The oil in

the grease would disrupt the

reference air and the function of the

heated oxygen sensors (HO2S).

The engine control module (ECM) can

diagnose the heated oxygen sensor. For

further information, see Heated oxygen

sensor (HO2S) diagnostic . VIDA can be

used to read off the calculated lambda

value from the heated oxygen sensor.

Rear heated oxygen sensor (HO2S)

The rear heated oxygen sensor (HO2S) is

used to provide the Engine Control

Module (ECM) with information about the

remaining oxygen content of the exhaust

gases beyond the three-way catalytic

converter (TWC). This information is

used by the Engine Control Module

(ECM) to check the function of the three-

way catalytic converter (TWC). This

check is carried out when the conditions

for the catalytic converter diagnostics

have been met. The rear heated oxygen

sensor (HO2S) has no direct effect on

regulation of the fuel/air mixture.

However the Engine Control Module

(ECM) uses the signal to optimize the

signal from the front heated oxygen

sensor (HO2S). For further information,

see:

For S60/ S80/ V70/ V70XC/ XC70:

Three-way catalytic converter (TWC)

diagnostics .

For XC90: Catalytic converter

diagnostic .

The heated oxygen sensor (HO2S) uses

voltage control. The signal characteristic

is binary. With a binary signal

characteristic, the amplitude of the signal

curve changes considerably when

changing the oxygen content in the

exhaust gases. Otherwise its components

and function are the same as the front

heated oxygen sensor (HO2S).

Caution! The wiring for the heated

oxygen sensors (HO2S) must not be

trapped or damaged in any way. The

connectors for the heated oxygen

sensors (HO2S) must not be greased



under any circumstances. The oil in

the grease would disrupt the

reference air and the function of the

heated oxygen sensors (HO2S).

The engine control module (ECM) can

diagnose the rear heated oxygen sensor.

The signal can be read using VIDA.

Preheating of the heated

oxygen sensors (HO2S)

The heated oxygen sensor

(HO2S) only functions above a

certain temperature,

approximately 300 °C. The

normal operating temperature

is between 300-900 °C. The

heated oxygen sensors

(HO2S) are electrically pre-

heated so that operating

temperature is rapidly

reached. This also ensures

that the heated oxygen

sensors (HO2S) maintain a

normal operating temperature

and to prevent condensation

which could damage the


The heater element in the

probe consists of a positive

temperature coefficient (PTC)

resistor. The system relay

supplies the heater element

with voltage. The element is

grounded in the engine control

module (ECM). When the

control module grounds the

connection a current flows

through the PTC resistor.

When the heated oxygen

sensor (HO2S) is cold, the

resistance in the PTC resistor

is low and a large current will

flow through the circuit. The

current from the Engine

Control Module (ECM) is

pulsed at first to prevent

condensation damage to the


Depending on the

temperature, allowances are

made for factors such as the

dew point. As the temperature

in the PTC resistor rises, the

resistance rises, the current

falls and switches in stages to

a constant current. The pre-

heating time for the front

heated oxygen sensor (HO2S)



is short, approximately 20

seconds.

Probe preheating begins as

soon as the engine is started.

The heater element heats the

heated oxygen sensors

(HO2S) to approximately 350

°C. The probes maintain this

as a minimum temperature.


(ECM) can diagnose the heater

element.

Engine coolant

temperature (ECT) sensor

The engine coolant

temperature (ECT) sensor

checks the temperature of the

engine coolant. The

temperature of the engine

coolant is required so that the


can regulate:

� the injection period

� the idle speed

� the engine cooling fan

(FC)

� the ignition advance

� engagement and

disengagement of the

A/C compressor

� diagnostic functions.

The sensor is a negative

temperature coefficient (NTC)

type which is supplied with

power from the control

module (signal) and is


module.


changes depending on the

temperature of the coolant.

Depending on the resistance

in the sensor, a voltage

(signal) is transmitted to the

Engine Control Module (ECM).

At 0 °C, the voltage is

approximately 4.0 V. At 100 °

C the voltage is approximately



0.5 V. Low temperature

results in high voltage (high

resistance), high temperature

in low voltage (low

resistance).

The engine coolant

temperature (ECT) sensor is

located beside the thermostat.


(ECM) can diagnose the

engine coolant temperature

sensor. The sensor value can

be read off using VIDA.

Engine cooling fan (FC) /

engine cooling fan (FC)

control module

The engine cooling fan (FC)

has two functions. One is to

cool the engine compartment,

the other is to cool the

condenser when the air

conditioning (A/C) compressor

is working.


(ECM) transmits a pulse width

modulated (PWM) signal to

the engine cooling fan (FC)

control module. The control

module then activates the fan

at different speeds. The speed

of the engine cooling fan (FC)

is determined by the engine

control module (ECM),

depending on the coolant

temperature (based on the

signal from the engine coolant

temperature (ECT) sensor)

and the vehicle speed.

The temperature conditions

for engagement of the

different engine cooling fan

(FC) stages may vary slightly,

depending on the engine

variant and the equipment

level.



The temperature conditions

apply when:

� the A/C is off

� no faults are detected by

the Engine Control

Module (ECM).

Note! The engine cooling

fan may have a post-run of

up to approx. 6 minutes

after the engine has been

turned off. The time for the

fan's post-run depends on

engine temperature,

temperature in the engine

compartment and pressure

level in the AC-system.

Warning! Be careful since

the engine cooling fan may

have a post-run after the

engine has been turned off.

The engine cooling fan (FC)

and its control module are

behind the radiator.



engine cooling fan. The fan

can be activated using VIDA.

Cooling fan for control

modules, turbocharger

(TC) (certain markets only)

The function of the cooling fan

is to cool the control modules

in the control module box in

the engine compartment. The

control modules may be

damaged if they overheat.


(ECM) activates the fan

depending on the signal from

the engine coolant

temperature (ECT) sensor and

the temperature sensor in the

control module.

The cooling fan is in the hose

between the control module

box and the firewall.





cooling fan. The fan can be

activated using VIDA.

A diagnostic trouble code

(DTC) is stored if the

temperature in the engine

control module (ECM) gets too

high.

Mass air flow (MAF) sensor

(2002-2004)

The mass air flow (MAF)

sensor gauges the air mass

sucked into the engine. It

continuously transmits signals

to the engine control module

(ECM) about the mass of the

intake air. This data is used by

the engine control module

(ECM) to calculate:


� the ignition timing

� turbocharger (TC) boost

pressure (turbocharged

engines only)

� the engine load.

The transmission control

module (TCM) also uses this

data for its gear shift

calculations. This data is

transmitted to the

transmission control module

(TCM) from the engine control

module (ECM) via the high

speed side of the Controller

area network (CAN).


sensor consists of a plastic

housing with connectors, test

electronics and an aluminum

heat sink. The test electronics

in the mass air flow (MAF)

sensor consist of a hot film

comprised of four resistors.

The hot film is cooled by the

air flow to the engine.


sensor is supplied with battery



voltage by the system relay

and is grounded in the engine

control module (ECM). The

signal from the sensor is

analogue and varies between

approximately 1-5 V

depending on the air mass.

Low air flow (low mass)

results in low voltage, high air

flow (high mass) gives high

voltage. No air flow gives a

reading of approximately 1 V.


sensor is positioned between

the air cleaner (ACL) housing

and the intake manifold.

The shape of the mass air flow

(MAF) sensor is slightly

different on naturally

aspirated engines and also

contains an air temperature

sensor.


(ECM) can diagnose the mass

air flow (MAF) sensor. The

signal can be read using VIDA.

Mass air flow (MAF) sensor

(2005-)


sensor measures the air mass

sucked into the engine. On

naturally aspirated engines

and 5 cylinder turbocharged

engines (except B5254T2/-

T4), it also measures the

temperature of the intake air.

Air mass


sensor transmits signals to the


about the mass of the intake

air. This data is used by the


to calculate:


� the ignition timing

� turbocharger (TC) boost



pressure (turbocharged

engines only)

� the engine load.

The transmission control

module (TCM) also uses this

data for its gear shift

calculations. This data is

transmitted to the

transmission control module

(TCM) from the engine control

module (ECM) via the high

speed side of the Controller

area network (CAN).


sensor consists of a plastic

housing with connectors, test

electronics and an aluminum

heat sink. The test electronics

in the mass air flow (MAF)

sensor consist of a hot film

comprised of four resistors.

The hot film is cooled by the

air flow to the engine.


sensor is supplied with battery

voltage by the system relay

and is grounded in the engine

control module (ECM). The


analogue and varies between

approximately 1-5 V

depending on the air mass.

Low air flow (low mass)

results in low voltage, high air

flow (high mass) gives high

voltage. No air flow gives a

reading of approximately 1 V.

Intake temperature

The temperature sensor

detects the temperature of the

intake air after the charge air

cooler (CAC). This data is used

by the engine control module

(ECM) to calculate the boost

pressure control (turbocharger

(TC) and to calculate the

injection period. The control

module also controls certain

diagnostic functions using the

signal from the temperature

sensor.

The sensor, which is an NTC

resistor, is grounded in the

control module and supplied

with power (signal) from the

control module. The resistance

in the sensor changes

according to the temperature



of the intake air. This provides

the control module with a

signal of between 0-5 V. The

lower the temperature the

higher the voltage (high

resistance). A high

temperature results in low

voltage (low resistance).


sensor is positioned between

the air cleaner (ACL) housing

and the intake manifold.


(ECM) can diagnose the air

mass and intake temperature

of the mass air flow sensor.

The signals can be read using

VIDA.

Manifold absolute pressure

(MAP) sensor, intake

(turbocharged engines

only, 2002-2004)

The manifold absolute

pressure (MAP) sensor detects

the pressure in the intake

manifold downstream of the

charge air cooler (CAC). The


primarily used by the engine

control module (ECM) to check

that the correct boost

pressure is reached. The boost

pressure is governed by the

turbocharger (TC) control

valve.

The sensor, which is a piezo



with 5 V from the control

module.



pressure in the intake

manifold, giving a signal of 0 -

5 V. Low pressure results in

low voltage, high pressure in

high voltage.





manifold absolute pressure

sensor. The sensor signal can

be read using VIDA.


pressure (MAP) sensor is in

the intake hose for the throttle

body (TB).

Manifold absolute pressure

(MAP) sensor, intake


only, 2005-)


pressure (MAP) sensor detects

the pressure in the intake

manifold downstream of the

charge air cooler (CAC). On 6

cylinder turbocharged engines

and B5254T2/-T4, the

temperature of the intake air

is also detected.

Pressure sensor

The signal from the sensor is

primarily used by the engine

control module (ECM) to check

that the correct boost

pressure is reached. The boost

pressure is governed by the

turbocharger (TC) control

valve.

The sensor, which is a piezo



with 5 V from the control

module.



pressure in the intake

manifold, giving a signal of 0 -

5 V. Low pressure results in

low voltage, high pressure in

high voltage.

Intake temperature















sensor.





control module.


changes according to the


This provides the control

module with a signal of

between 0-5 V. The lower the

temperature the higher the

voltage (high resistance). A

high temperature results in

low voltage (low resistance).



manifold absolute pressure

sensor. The sensor signal can

be read using VIDA.


pressure (MAP) sensor is in

the intake hose for the throttle

body (TB).

Leak diagnostic unit

(certain markets only)

The function of the leak

diagnostic unit is to pressurize

the fuel tank system during

leak diagnostics.

The leak diagnostic unit

consists of a plastic housing

with:

1. electrical air pump

2. a valve / solenoid which

governs the air flow in

the unit

3. a heater element (PTC

resistor) which warms

up the pump.



The electrical pump, valve and

heater element in the unit are

supplied with voltage by the

system relay. The pump, valve

and heater element are

grounded (control) in the


Note! On model years,

2002-2004 the heating

element was controlled by

the Central electronic

module (CEM), but on

request from the Engine


During leak diagnostics the

pump in the leak diagnostic

unit starts. The valve in the

unit is operated by the engine

control module (ECM) by

grounding the different circuits

internally in the engine control

module (ECM).

The Engine control module

(ECM) checks the fuel tanks

system for leaks by

pressurizing the system and at

the same time monitoring a

number of relevant

parameters. Also see: Leak

diagnostics (certain markets

only)


(ECM) can diagnose the leak

diagnostic unit.

The valve in the leak

diagnostic unit can be

activated.

The leak diagnostic unit is at

the upper front edge of the

fuel tank.

Outside temperature

sensor

The outside temperature

sensor detects the

temperature in the

surrounding air. The signal is

used by the engine control

module (ECM) as a substitute



value in the event of a fault in

certain components or

functions and to control

certain diagnostic functions.

The sensor is a negative

temperature coefficient (NTC)

type which is supplied with

power from the control

module (signal) and is


module.

The resistance in the sensor,

which provides a signal

between 0-5 V, changes

depending on the outside

temperature. Low

temperatures produce high

voltage (high resistance), high

temperatures produce low


The outside temperature

sensor is positioned in the left

door mirror.



outside temperature sensor.

The sensor value can be read

off using VIDA.

Engine speed (RPM) sensor

The engine speed (RPM)

sensor provides the Engine

Control Module (ECM) with

information about the speed

and position of the crankshaft.


(ECM) is able to use the signal

from the engine speed (RPM)

sensor to determine when a

piston is approaching top dead

center (TDC). However it is

unable to use the signal from


sensor to determine whether

the piston is in the combustion

stroke or whether the exhaust

valve is open (exhaust

stroke). The signal from the

camshaft position (CMP)

sensor is also required to



determine the operating cycle

of the engine.

The signal from the engine

speed (RPM) sensor is also

used to check the engine for

misfires. For further

information, see Misfire

diagnostics .

Cars with manual

transmissions have a series of

holes drilled in the periphery

of the flywheel. Cars with

automatic transmissions have

a steel ring with punched

holes. This steel ring is welded

to the edge of the carrier

plate. In both cases, there is

6° between each hole. This

arrangement creates a hole

for each tooth. There are 360°

in one revolution. 6° between

each hole means that there

are 60 holes. However one

hole is not drilled/punched, to

create a reference position

(tooth) for the crankshaft.

This reference position is 72°

before the top dead center

(TDC) of cylinder 1 on a 5

cylinder engine.

The engine speed (RPM)

sensor is at the rear of the

engine above the flywheel.

The sensor is inductive with a

permanent magnet. An

alternating current is induced

in the sensor when the

flywheel/carrier plate passes


sensor. The generated voltage

and frequency increases with

the engine speed (rpm). The

signal varies between 0.1-100

V depending on the engine

speed (RPM).


(ECM) is able to determine the

engine speed (RPM) by

counting the number of holes

per time unit. When the

reference tooth passes the

engine speed (RPM) sensor,

the voltage and frequency

drop momentarily to zero,

even though the engine is still

running. This allows the


to determine the position of

the crankshaft.



The following applies to

model year 2002 onwards:

If the signal from the engine

speed (RPM) sensor is

incorrect or missing, the

control module will use the

signals from the camshaft

position (CMP) sensor, on the

condition that the position of

the camshaft has been

adapted and the car can be

driven if there is no signal.



engine speed (RPM) sensor.

The sensor value (engine

speed (rpm)) can be read off

using VIDA.

Camshaft sensor

The function of the camshaft

position (CMP) sensor is to

detect the camshaft flanks.

The signal from the sensor is

used by the engine control

module (ECM) to determine

the radial position of the

camshaft.

Each camshaft has four flanks

per camshaft revolution. A

pulse wheel on the camshaft

consisting of four teeth (the

teeth are positioned by each

flank) is used by the camshaft

position sensor (CMP) to

detect the flanks.

The flanks are not symmetric

on the camshaft. This allows

the control module to

determine which flank has

been detected and therefore

which operating cycle the

camshaft is in.

When the operating cycle of

the camshaft is established,

the control module is able to

determine which cylinder

should be ignited. In the event

of misfire or engine knock, the

control module is also able to



determine which cylinder is

misfiring or knocking. Also see

Design:Knock sensor (KS) and

Design:Engine speed (RPM)

sensor .

Data about the position of the

camshaft is used during

camshaft control (CVVT). See

Function:Camshaft control

(CVVT) .

The sensor, which is a

magnetic resistor with a

permanent magnet, is


module and supplied with 5 V

from the control module.

When one of the teeth on the

camshaft pulse wheel passes

the camshaft position (CMP)

sensor, a signal is transmitted

to the control module from the


sensor. The signal varies

between 0-1 V and is low

when a flank passes the


sensor.

The camshaft position (CMP)

sensor is positioned at the

rear of the engine by the

controllable camshaft (CVVT).




sensor.

Knock sensor (KS)

The function of the knock

sensor (KS) is to monitor

combustion knocking from the

engine. Knocking may damage



the engine and reduces the

efficiency of engine

combustion.

If the engine control module

(ECM) registers knocking from

any of the cylinders, the

ignition will be retarded for

that cylinder at the next

combustion stage. If repeated

ignition retardation does not

prevent knocking, the

injection period will be

increased. This has a cooling

effect. On turbocharged

engines the boost pressure

will also be lowered, reducing

the engine load.

The sensor is made up of a

Piezo electrical crystal. If there

is engine knock, vibrations

(sound waves) spread through

the cylinder block to the knock

sensor (KS). The resultant

mechanical stress in the piezo

electrical material in the knock

sensors generates a voltage.

This signal is transmitted to


(ECM). The signal corresponds

to the frequency and

amplitude of the sound waves.

This allows the Engine Control

Module (ECM) to determine if

the engine is knocking. The


sensor and engine speed

(RPM) sensor are used to

determine the operating cycle

of the engine (which cylinder

is igniting) and thereby which

cylinder is knocking.

The knock sensors (KS) are

positioned on the cylinder

block below the intake

manifold.


(ECM) can diagnose the knock

sensors (KS).

Electronic throttle unit



The electronic throttle unit,

using the control signal from


(ECM), regulates the amount

of air for engine combustion.

This is done using an

electronic shutter.

The electronic throttle unit

consists of a round throttle

disc on a shaft. This is turned

using a DC motor (damper

motor), gear wheel and two

springs, an opening spring and

a return spring. The damper

motor is controlled by the


and is supplied with power by

an integrated power stage in

the control module. At one of

the limit positions the throttle

disc is closed so that no air

can pass the throttle unit. At

the other limit position the

throttle disc is parallel to the

air flow so that the air is able

to freely pass through the

throttle unit. The throttle disc

shaft is mechanically

connected to two built-in

potentiometers (position

sensors) which are supplied

with power by the control

module. The signals from the

potentiometers provide the

control module with data

about the position of the

throttle disc. The electronic

throttle unit has a connector

with six gold plated pins.

Note! A damaged terminal

pin surface can interfere



with the function

1. Current channels,

potentiometers

2. Contact strips,

potentiometers

3. Spring

4. Spring

5. Throttle disc

6. Damper motor

7. Gear wheel

8. Gear sector

9. Connector.

The electronic throttle unit is

located on the engine intake

manifold.

In the event of a fault, the

throttle unit must be replaced

as a single unit.



electronic throttle unit.

Throttle position (TP)

sensor

See Design:Electronic throttle

unit .

Accelerator pedal (AP)

position sensor

The function of the accelerator

pedal (AP) position sensor is

to provide the engine control

module (ECM) with

information about the position

of the accelerator pedal. This

data is used by the control

module to deploy the shutter

in the throttle unit to the

correct angle.

The sensor consists of a

plastic housing with two

potentiometers, an

Analog/Digital converter and

circuits. The potentiometers

are connected to a shaft which

is affected by the position of

the accelerator pedal (AP).

The resistance in the

potentiometers changes with



the position of the accelerator

pedal (AP).

The accelerator pedal (AP)

position sensor transmits an

analogue and a digital signal

(pulse width modulated (PWM)

signal) to the control module.

These signals indicate the

position of the accelerator

pedal (AP). The digital signal

is generated by the sensors

Analog/Digital converter.

The analog and digital signals

are used at the same time by

the control module to regulate

the throttle shutter angle.

The sensor is supplied with 12

V by the system relay via a

fuse and is grounded to the

body.

The digital signal is also used

in conjunction with the analog

signal for accelerator pedal

position sensor diagnostics.


position sensor signals can be

read off using VIDA. A

diagnostic trouble code (DTC)

is stored if the engine control

module (ECM) detects a

difference between the analog

and digital signals. The engine

control module (ECM) then

uses a minimal value to

ensure the function (limp

home).


position sensor is located on

the accelerator pedal bracket.

Engine coolant level sensor

The function of the engine

coolant level sensor is to alert

the driver if the engine coolant

level in the expansion tank is

too low.

The sensor is a magnetic reed

switch, which is enclosed in a

pipe on the bottom of the



expansion tank. Around the

pipe, on the inside of the

expansion tank is a float. This

float contains a magnet. When

the engine coolant level is

above minimum, the float is

too high in the tank to affect

the switch. However if the

engine coolant level falls

below the minimum level, the

magnetic field acts on the

switch.

The sensor is supplied with

voltage (signal) from the

Engine Control Module (ECM)

and grounded in chassis.

When the engine coolant level

in the expansion tank is over a

certain level the circuit closes,

which produces a low signal.

When the engine coolant level

is below a certain level the

circuit is opened by the engine

coolant level sensor, which

produces a high signal. When


(ECM) detects a high signal

the information about low

engine coolant level is

transmitted via the Controller

area network (CAN) to the

driver information module

(DIM), which warns the driver.

Note! There are no

functions controlled by the

engine which are directly

connected to the low

coolant level warning lamp.


(ECM) only transfers the

signal which is used by the

Driver Information Module

(DIM).

The following applies from

model year 2005-

The signal of the engine

coolant level sensor can be

read using VIDA.


(ECM) cannot diagnose the

engine coolant level sensor.

Temperature sensor, intake


only, 2002-2004)



On naturally aspirated

engines, the intake air

temperature sensor is

integrated in the mass air flow

(MAF) sensor. On model year

2002 turbocharged engines,

the temperature sensor is a

stand-alone component. On

turbocharged engines from

model year 2003, the

temperature sensor is

integrated in the intake air

pressure sensor.













sensor.





control module.




This provides the control

module with a signal of

between 0-5 V. The lower the

temperature the higher the

voltage (high resistance). A

high temperature results in

low voltage (low resistance).



The temperature sensor is

between the air cleaner (ACL)

housing and the intake

manifold (does not apply to

turbocharged engines 2003-).

The temperature sensor on

turbocharged engines 2003- is

integrated in the intake air

pressure sensor.



temperature sensor. The

sensor signal can be read

using VIDA.

Fuel pressure sensor / fuel

temperature sensor (only

vehicles with demand

controlled fuel pumps)

The fuel pressure sensor is

combined and consisted of

both the fuel pressure sensor

and the fuel temperature

sensor. The sensor detects the

fuel pressure (the absolute

pressure) and the temperature

of the fuel in the fuel rail.

Fuel pressure sensor

The pressure sensor is a Piezo

resistive type resistor, the

resistance of which changes

with the pressure. Depending

on the pressure in the fuel

rail, an analog signal of 0-5 V

is transmitted. Low pressure

results in low voltage, high

pressure in high voltage.


(ECM) then uses this signal to

adjust the pressure in the fuel

rail using the fuel pump

control module. Also see

Function:Fuel pressure

regulation (only vehicles with


pumps) .

The pressure sensor is

supplied with 5 V and

grounded in the engine control



module (ECM). The pressure

sensor transmits a signal

indicating the fuel pressure to


(ECM) on a separate cable.


(ECM) can diagnose the fuel

pressure sensor. Its signals

(pressure and temperature)

can be read using VIDA.

Note! The absolute

pressure is displayed when

using VIDA parameter

readout to read off the fuel

pressure. If there is no

pressure at the fuel rail,

the atmospheric pressure

will be displayed.

Hint:

The relative pressure

(absolute pressure minus

atmospheric pressure) is

displayed when reading off the

fuel pressure via a manometer

connected to the fuel rail.

Fuel temperature sensor

The temperature sensor is an

NTC sensor. The sensor is

supplied with voltage (signal)

from and grounded in the




temperature of the fuel. This

provides the engine control

module (ECM) with a signal of

between 0-5 V. Low

temperature results in high

voltage (high resistance). High

temperature results in low



(ECM) uses the signal to

calculate the volume of the

fuel.

The fuel pressure sensor is on

the left-hand end of the fuel

rail.

Oil level sensor (2004-,

certain markets and

models only)



The oil level sensor provides


(ECM) with information about

the quality and temperature of

the engine oil and the oil level

in the oil trough. Which of

these functions is used by the

sensor varies between

different car models.

All three functions are

combined in one unit with a

sensor section and an

electronics section. There are

no moving parts in the sensor.

The sensor consists of:

� a terminal with three

pins

� integrated electronics

� 2 capacitive gauge

elements

� a PTC resistor.

The oil level sensor is supplied

with 5 V by the engine control

module (ECM). The oil level

sensor generates a PWM

signal for the engine control

module (ECM). Also see

Function:Oil level monitoring

(2004-, certain markets and

models only) .



functions of the oil level

sensor. Also see Oil level

sensor, diagnostics .

The pulse-width modulated

(PWM) signal from the oil level

sensor can be read using

parameter readout.

Main relay (system relay)



The function of the main relay

(system relay) is to supply

certain components with

voltage.

The relay is mechanical and

has a closing function. In the

rest position the circuit in the

relay is open.

The main relay terminals (#30

and #86) are supplied with

voltage by the battery. When

the ignition key has been

turned and the Engine Control

Module (ECM) is powered, the

terminal (#85) on the main

relay is grounded by the

Engine Control Module (ECM).

When the terminal (#85) is

grounded, the relay is

activated and a number of

components are powered via

the relay terminal (#87).


(ECM) can diagnose the main

relay.

The main relay is in the

relay/fusebox in the engine

compartment.

Air conditioning (A/C)

relay


relay supplies the A/C

compressor with voltage. The

relay is controlled by the


based on information from

different signals:

� the climate control

module (CCM) (via the

control area network

(CAN))

� the engine coolant

temperature

� the position of the

accelerator pedal (AP)

� the pressure in the

system.




(ECM) can temporarily

disengage the A/C compressor

during wide open throttle

(WOT) acceleration.

The relay is mechanical. It has

a closing / breaking function

and is supplied with power

from the system relay.

In the rest position the circuit

in the relay is open.

The system relay supplies the

coil and the relay with power.

The relay activates when the

coil is grounded in the engine

control module (ECM), the

circuit closes and the A/C

compressor is supplied with

power via the relay voltage

output.

The relay coil is grounded

(signal) when the engine

control module (ECM) receives

a signal via the Controller area

network (CAN) from the

climate control module (CCM)

to activate the relay and start

the compressor.

Fuel pump (FP) relay,

(2002–2004)

For information about the fuel

pump (FP) relay for model

year 2005-, see Design and

Function, central electronic

module (CEM).

The following applies for

model year 2002–2004

The fuel pump (FP) relay

supplies the fuel pump with

power. The relay also cuts the

power to the pump when the

ignition is switched off or if the

engine stops. In cars with


pumps, the above function

applies to the fuel pump

control module. The central

electronic module (CEM) also

cuts the power to the relay if

the supplemental restraint



module (SRS) transmits a

message indicating that an

airbag has deployed.

The central electronic module

(CEM) activates and

deactivates the relay when

requested by the engine

control module (ECM) (via the

Controller area network

(CAN)).

See Design and Function,


(CEM).

When the ignition is switched

on, the engine control module

(ECM) sends a signal to the


(CEM) via the controller area

network (CAN) to run the fuel

pump (FP) for one seconds.

This is so that the pressure

increases in the fuel system,

shortening the start time.

When the flywheel in the

engine rotates (generating a

signal from the engine speed

(rpm) sensor), the engine

control module (ECM) will

transmit a request to the


(ECM) via the controller area

network (CAN) to start the

fuel pump. In the event of the

engine stopping, the Engine

Control Module (ECM) cancels

the "activated fuel pump"

signal. The central electronic

module (CEM) then switches

off the fuel pump.

There is a directly connected

cable between the engine

control module (ECM) and the


(CEM). In the event of a fault

in the controller area network

(CAN), this cable is used for

the "activated fuel pump"

signal.

Injectors



The function of the injectors is

to spray fuel into the cylinders

in the correct spray patterns.

This happens sequentially.

The injectors are in the intake

manifold.

It is essential that the

injectors are correctly installed

with no air leakage around

them. Fuel leakage from the

top of an injector when it is

not activated may lead to

starting and driving problems.


(ECM) controls the injectors

using a pulse width

modulation (PWM) signal.

The injectors for each cylinder

have different terminals in the

engine control module (ECM),

depending on whether the

engine has 5 or 6 cylinders.



injectors. The injectors can be


evaporative emission

system (EVAP) valve

The evaporative emission

system (EVAP) valve is used

to open/close the connection

between the EVAP canister

and the intake manifold. The

valve controls the flow of

hydro-carbons (fuel vapor)

from the EVAP canister to the

engine intake manifold using

the vacuum in the intake

manifold. This ensures that

hydro-carbons stored in the

EVAP canister are used in the

engine combustion process.

The valve is an electro-

magnetic valve which is

powered from the system

relay. When the valve needs

to be opened, it is grounded




module (ECM). The

evaporative emission system

(EVAP) valve is closed when in

the standby position (open-

circuit).

When the control module

requests that the EVAP

canister should be emptied

(the hydrocarbons stored in

the canister should be

released into the engine), the

control module deploys the


(EVAP) valve by grounding it.

The valve is grounded using a

pulse width modulation (PWM)

signal, allowing the control

module to govern the extent

to which the valve opens and

adapting the emptying of the

canister according to how full

it is, engine speed (rpm) and

load etc.




(EVAP) valve. The valve can

be activated using VIDA.

The evaporative emission

system (EVAP) valve is close

to the intake manifold.

Camshaft reset valve

(Continuous variable valve

timing (CVVT))

The camshaft reset valve

controls the oil flow to the

CVVT unit (camshaft pulley).

The valve consists of an

electro-magnetic valve with a

spring-loaded piston. There

are slits in the piston which

channel the engine lubricating

oil to the CVVT unit by moving

the piston in the reset valve.

The continuous variable valve

timing (CVVT) unit turns the

camshaft (the cam timing

changes). The direction in

which the camshaft turns



depends on the chamber in

the CVVT unit which is

supplied with oil (pressure).

Also see Function:Camshaft

control (CVVT) .

The system relay supplies the

reset valve with voltage. The

valve is grounded (control

stage) in the engine control

module (ECM). When the

valve is grounded using a


signal, the oil flow in the valve

can be controlled to the

different chambers in the

continuous variable valve

timing (CVVT) unit at variable

rates. This allows the cam

timing to be changed precisely

and steplessly.



camshaft reset valve.

The valve is on the cylinder

head above the camshaft with

camshaft control.

Turbocharger (TC) control

valve

The turbocharger (TC) control

valve is used to open/close

the connection between the

intake manifold and the

pressure servo for the

turbocharger (TC). The valve

controls the pressure servo

which affects the boost

pressure control (BPC) valve

and therefore the boost

pressure. Also see

Function:Turbocharger (TC)

control system .



The valve is an electro-

magnetic valve which is

powered from the system

relay. When the valve needs

to be opened, it is grounded


module (ECM). The valve can

be controlled steplessly by

grounding the valve using a


signal.

The valve is closed when in

the standby position (open-

circuit).

The turbocharger control valve

can be diagnosed and can be


The turbocharger (TC) control

valve is on a hose between

the intake manifold and the

pressure servo for the

turbocharger.

Ignition coils

The ignition coils supply the

spark plugs with high voltage

to produce sparks. The engine

control module (ECM) controls

the ignition coils so that

sparks are generated at the

correct time.

Each ignition coil has its own

integrated power stage.

The ignition coils are in the

sparkplug wells above each

spark plug.

The ignition coils for each

cylinder have different

terminals in the engine control

module (ECM), depending on

whether the engine has 5 or 6

cylinders.



ignition coils.

Emissions warning lamp



The emissions warning lamp in

the Driver Information Module

(DIM) has a warning symbol.

This warning symbol varies

depending on the market and

model year. The warning

symbols are:

� "Engine symbol" (not

USA, model year 2001-)

� "CHECK ENGINE" (MIL -

Malfunction Indicator

Lamp, USA only).

� "Lambda symbol" (not

USA, model year 1999-

2000).

The warning symbol lights

when the ignition key is

turned to position II and goes

out when the engine is started

if the engine management

system does not detect any

faults.

The warning lamp is directly

connected to the engine


The warning lamp will light if

there is a fault in one of the

parameters in the engine

management system. The

warning lamp will also light in

response to a request

transmitted via the Control

area network (CAN) if there is

a fault in one of the following

systems which affects

emissions:

� transmission control

module (TCM)

� brake control module

(BCM).

7/11/2014 PRINT





Documents

284: Bosch ME7.01 Engine management system, B5254T2